System and method for treating fish

ABSTRACT

A system for removing parasites from fish includes a conduit through which individual fish pass, a plurality of arms associated with the conduit circumferentially spaced with respect to each other, and a spray nozzle for each arm connected to a fluid source for dislodging parasites from said fish. The nozzles are closely spaced with respect to the fish for more effective treatment. A pre-treatment substance may also be used.

RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 15/914,374 filed Mar. 7, 2011 which claims benefitof and priority to U.S. Provisional Application Ser. No. 62/461,692filed Mar. 8, 2017, under 35 U.S.C. §§ 119, 120, 363, 365, and 37 C.F.R.§ 1.55 and § 1.78, and is incorporated herein by this reference.

FIELD OF THE INVENTION

This subject invention relates to methods and systems for treating fish(e.g., salmon) to rid them of parasites. (e.g., see lice).

BACKGROUND OF THE INVENTION

Fish farming is a large business but the damage caused by parasites costfish farmers huge sums of money each year. Chemical treatments (see,e.g., U.S. 2013/0095126, incorporated herein by reference) may beineffective and/or costly, may damage or kill the fish, and/or maypollute the water and/or damage other organisms. Certain pesticides,drugs, vaccines, and the like may result in genetically resistant sealice.

Warm water and/or fresh water treatments may be ineffective, expensive,and often require long treatment times. Moreover, if the sea lice becomeresistant to fresh water, then wild saltwater fish migrating in freshwater can be put at risk.

Some mechanical treatments have been proposed. For example, WO 98/24314,incorporated by reference herein, proposes using water jets to removesea lice from salmon. But, the water jets are fixed in place. Since thesalmon are not stationary, and are not a constant size, large fish maybe damaged by the water jets and, for smaller fish, the jet pressure maynot be great enough to effectively remove the sea lice. Moreover, thewater from the spray nozzles has to travel through water before reachingthe surface of the fish body lowering the effectiveness of the waterjet. And, the water jets are in a single fixed configuration with fixedangles.

BRIEF SUMMARY OF THE INVENTION

In one preferred method and system, fish (e.g., salmon) are treated intwo zones in a cost effective and expedient manner to more effectivelyremove parasites (e.g., sea lice) from the fish. The throughput of thepreferred system results in many fish being treated in a short amount oftime. Parts of the process may include a batch treatment or the systemmay be configured for a continuous process. In the first treatment zone(which may be optional), the fish are subject to a treatment that killsand/or weakens the parasites. This may include chemical treatments, forexample, some son of osmotic de-regulation that may be used in the firstzone for killing, paralyzing, and/or weakening the parasites.Optionally, or in addition, the pH level of the sea water in the firsttreatment zone may be adjusted up or down, or both, to speed andincrease the effectiveness of the treatment. Other substances such ashydrogen peroxide may be used. Other treatments may include varyingtemperature, salinity, dissolved gases. light exposure, or any othermethods including sound, pressure, ultrasound, electrostatic,electromagnetic, laser, and/or plasma exposure (hat may kill or weakenthe parasites. The parasites may be killed or weakened by thetreatment(s) in the first treatment zone. Some parasites may be weakenedor temporarily paralyzed but still attached to the fish. Other parasitesmay be released from the fish in live first treatment zone.

In the second treatment zone, physical treatments, (e.g., fishagitation, water jets sprayed through air at the fish) remove parasitesfront the fish. The removed parasites and their eggs (if any) may becollected by the system, killed (if still alive) and may be used as food(e.g., food for the fish that were previously treated), or for otherpurposes. The dead parasites may also be collected and simply dischargedback into the ocean. This also applies to the parasite's egg-strings andloose eggs. Preferably, the fish are not stressed or harmed, theenvironment is not harmed, and the method and system are cost effective,90-100% of the parasites may be removed from the fish using the systemsdescribed herein.

The subject invention, however, in other embodiments, need not achieveall these objectives and the claims hereof should not be limited tostructures or methods capable of achieving all of these objectives.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Other objects, features and advantages will occur to those skilled inthe art from the following description of a preferred embodiment and theaccompanying drawings, in which:

FIGS. 1A and 1B is a block diagram showing an example of the primarycomponents associated with a system for and method of treating fishwhere the first treatment zone is a batch subsystem;

FIG. 2 is a schematic view showing an example of a treatment system inaccordance with the block diagram of FIGS. 1A and 1B;

FIG. 3 is a block diagram showing the primary components associated withan example of a system for and method of treating fish where the firsttreatment zone is continuous;

FIG. 4 is a schematic view showing an example of a system in accordancewith the block diagram of FIG. 3;

FIG. 5 is a schematic view showing an example of a mechanism fortreating fish in the first treatment zone;

FIG. 6 is a schematic view showing another mechanism for treating fishin the first treatment zone;

FIG. 7 is a schematic view showing another example of first and secondtreatment zones;

FIGS. 8A-8C are schematic views showing examples of spray heads mountedon pivoting arms in the second treatment zone keeping the spray headnozzles at a constant or near constant close distance and/or at a nearconstant, predefined angles with respect to the surface of the fish asit proceeds through the second treatment zone;

FIG. 9 is a schematic view showing an example of a spray head extendingfrom a shoe member;

FIGS. 10A-10C are schematic views showing a fish traveling through anexample of the second treatment zone where the spray heads are mountedto four bar linkages;

FIG. 11 is a schematic view showing fish directed through a radiallyexpandable chute and spray heads arranged on extendible and retractablepistons mounted to a ring disposed about the expandable chute;

FIGS. 12-14 are schematic views of spray nozzles attached to a radiallyexpandable chute;

FIG. 15 is a view showing how die spray nozzles maintain a constant jetangle to the surface of the fish and a constant water jet force alongthe surface of the fish; and

FIG. 16 includes views of another fish treatment system.

DETAILED DESCRIPTION OF THE INVENTION

Aside from the preferred embodiment or embodiments disclosed below, thisinvention is capable of other embodiments and of being practiced orbeing carried out in various ways. Thus, it is to be understood that theinvention is not limited in its application to the details ofconstruction and the arrangements of components set forth in thefollowing description or illustrated in the drawings. If only oneembodiment is described herein, the claims hereof are not to be limitedto that embodiment. Moreover, the claims hereof are not to be readrestrictively unless there is clear and convincing evidence manifestinga certain exclusion, restriction, or disclaimer.

FIG. 1 shows an example of a system for removing parasites from fishkept in pen 10 (which may be in the ocean). The system may, for example,be located on a vessel such as a barge or well boat. See US2016/0244130, incorporated by reference herein.

Fish in pen 10 are transported in sea water to the first treatment zone12. Various mechanisms can be used to transport fish in sea water, whichmay include: vacuum pumps, conveyors, or Archimedes' screws. See WO2014/129908 and also WO 2014/184776 both incorporated by referenceherein.

In first treatment zone 12, the fish may be treated with a substance(e.g., a solution) introduced into the treatment zone 12 as shown at 16.An exemplary dwell time may be 5-25 minutes. Preferred is an osmoticderegulator which weakens and/or kills sea lice on the fish. Examplesinclude Brine (CaCO3), iodine, potassium iodide, and lactic acid (e.g.four parts per thousand). Other possible treatments include knownchemicals and compounds. Adjusting other variables, such as dissolvedgases, salinity, and temperature, in conjunction with an osmoticderegulator or other treatment substance may decrease treatment time andimprove effectiveness. The pH level of the water in treatment zone 12may be adjusted to decrease treatment time and improve effectiveness.See, U.S. Pat. No. 8,759,073 incorporated by reference herein. Forexample, sodium hydroxide may be used to raise the pH of live sea waterwhile maintaining a safe level of pH and exposure time for the fish toapproximately 10.0. Hydrochloric acid may be used to lower the pH of thesea water to approximately 4.0 while maintaining a safe level of pH andexposure time for the fish. Again, the dwell time, in one example, maybe between two and thirty (e.g., five) minutes. If needed, the wateroutput from treatment zone 12 may be treated again to bring it back to anominal pH level (e.g., 8.3). Ozone may also be used in treatment zone12. See, for example, WO 2014/129908 and WO 2013/066191 (bothincorporated herein by this reference). The water temperature in thefirst treatment zone may be controlled to improve the effectiveness ofthe treatment and to improve the general health of the fish duringtreatment.

In treatment zone 12, some or all of the parasites will be killed or atleast weakened. One or more of the above described treatments as well asothers may be used in treatment zone 12. The parasites may be weakenedto the point they are not as strongly attached to the fish. Someparasites may be removed from the fish. The fish are then preferablytransferred to second treatment zone 18 where a physical treatment ispreferred to remove parasites from the fish. Treated fish with reducedparasites are then returned to a pen. The fish may optionally be sedatedfor the treatment in the first and/or second zone. The system mayfurther include separation zones 22 a, 22 b, and 22 c where lice (and/ortheir eggs) in the sea water and/or another solution present in thesystem are collected and exterminated at station 24. UV radiation may beused. Other extermination means may be used. The dead sea lice may betransported to storage vessel 26 for use as fish food, for example. Theseparation zones may include, for example, grates, filters, and the likethrough which water and any sea lice (and/or their eggs) pass but fishare directed to a different path. These separation zones ensure theparasites do not reattach themselves to the fish and ensure that anyeggs do not mature into parasites. There may be a singulation and/ororientation mechanism 28 upstream of treatment zone 18 so only a singlefish at a time, oriented head first, enters treatment zone 18.Singulation and/or orientation may also be performed manually with amechanism to present the fish to human operators for this purpose. Seawater may be sprayed on the fish in treatment zone 18 via pump 14 b.Pump 14 c may be used to pump sea water at separation zone 22 b to mixwith the treatment solution at 16 which is pumped into treatment zone12. Any removed sea lice and egg strings in the system due to sprayingof the fish, scraping of the fish, and/or due to movement of the fish,or treatment of any kind of the fish, may be removed from the system inseparation zone 22 c where water and removed sea lice are directed toextermination zone 24. In some examples, the fish are not swimming inthe sea water in second treatment zone 18.

FIG. 2 shows an example where a series of gates 30 a and 30 b are used.Fish are brought into optional separation zone 22 a via conduit 40 withgate 30 a open and gate 30 b closed until a predetermined amount of fishare present in chamber 32 a of treatment zone 12 in sea water. Weighingor some other process may be used to determine when a sufficient numberof fish are present in chamber 32 a.

A treatment solution or compound such as shown at 16 is then pumped intochamber 32 a to treat the fish for a predetermined dwell time afterwhich gate 30 b is opened and, the fish may be singulated and orientedat station 28 to travel within one or more conduits, 42 a, 42 b, 42 c oftreatment zone 18. The fish, after mechanical treatment in treatmentzone 18 then pass through separation zone 22 c and back into a pen.

A continuous flow system is shown in FIG. 3. Continuous flow may bebeneficial as the fish may be treated faster enabling a higherthroughput through the system. Continuous flow may also have theadvantage of exposing each fish more precisely to the treatment desiredfor the precise amount of time. Here, in treatment zone 12, the fish aretreated while they are singulated or at least in smaller groups andmoving in water. FIG. 4 also shows an example where treatment zone 12 isa continuous flow process as opposed to a batch process. Still, the fishspend a predetermined time in treatment zone 12 via, for example, aserpentine conduit 50. Alternatively, a motorized Archimedes screw 60,FIG. 5, inside conduit 62 may be used. In another version shown in FIG.6. coiled conduit 64 is fixed to motorized shaft 66 for treating fish 67for a predetermined dwell time in the first treatment zone 12. In stillanother version, die pocket feeder mechanism of U.S. 2005/0158430,incorporated by reference herein, may be used. Thus, the fish may bemoved along in water through first treatment zone while being treatedusing one or more of the mechanisms described above (or a similarmechanism).

Also, whenever the fish must be transported from one location to anotherin the overall system, the subsystems shown in FIGS. 4-6 or the pocketfeeder mechanism of U.S. 200/0158430 may be used. Other subsystems maybe used as well.

FIG. 7 shows an example of a system where a motorized vertical conveyor70 is used to bring fish 67 in sea water up to separation zone 22 awhere the sea water is removed from the system at separation zone 22through filter 72. Lice in the sea water may be further filtered out,killed, and collected as noted above.

Optionally, a treatment substance as shown at 16 is introduced into thesea water in vertical conveyor 70 to treat the fish and kill or at leastweaken the sea lice or oilier parasites as the fish move upwards in theconveyor. The pH of the sea water may be raised or lowered, a chemicalor biological agent may be used, the water may be warmed or cooled,and/or an osmotic treatment may be used. Other treatments may be used aswell. Thus, in this example, the device which moves die fish into thesystem is also the first treatment zone.

Then, the fish, now in air. travel in downwardly inclined conduit 42 andare subject to mechanical treatment in treatment zone IS. Preferably,the treatment zone 18 constitutes a continuous treatment subsystem. Inone preferred embodiment, a series of circumferentially oriented sprayheads are used. For example, there may three sets of spray heads withfour or eight spray heads in each set. If four spray heads are used,they may be oriented 90° apart and if eight spray heads are used theymay be oriented 45° apart. The spray heads function to dislodge theparasites from the fish. In separation zone 22 b, there is a grate orfilter as shown at 73 for removing from conduit 42 any fluid ejected bythe spray heads. Again, any sea lice (and/or eggs) in this fluid may befiltered out, collected, and/or destroyed. The conduit may be inclinedto provide the optimal velocity and efficacy e.g., between 5 and 90°with respect to horizontal. Killing the eggs in the system can preventlice from these eggs from returning which could create further problems.

Featured in some embodiments are spray heads which are urged close tothe fish 67 no matter their size. Also, the spray heads may beconfigured to always spray a fluid, (e.g., water or gas) at a constantangle relative to the fish outer surface. A treatment substance may alsobe added to the fluid supplied to the spray heads.

In systems with fixed spray heads, small fish may not receive enough ofa pressurized spray to dislodge sea lice and a large fish may receive apressurized spray at too high a pressure and/or velocity, and/ormomentum which damages the fish scales, eyes, fins, or the like. Thisproblem is addressed in the subject invention.

Also, any given fish body is small in diameter at the head, then largerin the middle, and them smaller again at the tail. Fixed in place sprayheads do not account for this change in fish geometry. This problem toois addressed in the subject invention as discussed below. Finally, priorsystems sprayed fluid towards the fish while the fish were in water. Thewater generally diminishes the effectiveness of the fluid jet spray bydiminishing the jet velocity and/or impact pressure, and/or momentum.This problem too is addressed in the subject invention since the fishpreferably travel in conduit 42 in air or other medium. In priorsystems, if the fish in water passed too dose to a given fixed jet sprayhead then the fish could be harmed including any damage to the eyes orother sensitive areas.

FIG. 8A shows an example where spray head 80 is mounted to the distalend of arm member 90 pivotably attached inside downwardly inclinedconduit 42. Fluid is supplied to spray head 80 via hose 92. Arm 90 isbiased away from conduit 42 via compression spring 94. Spray head 80 maybe further fitted with a shoe 96 which may pivot relative to arm 90 andwhich is biased via a spring 98 to an orientation parallel with thelongitudinal axis of the conduit. As shown in FIG. 9, spray head 80 mayrise above an orifice in shoe 96 and includes a nozzle 98. A grommet maysurround spray head 80 and is fitted to shoe 96. The nozzle 98 may beconfigured for delivering a fan spray of fluid. The fan spay could becurved in shape conforming to the fish body. In some embodiments, thenozzle and/or the spray head may pivot with respect to the arm it ismounted to. The spray head may then oscillate (e.g., between angles of 0to 90° or less).

In FIG. 8A, the spray from a nozzle (see nozzle 98, FIG. 9) is shown tobe tangential to the surface of the fish. In other embodiments, thespray may be at an angle relative to this tangent (e.g., 0-90°). Thenozzle may also deliver a spray angled appropriately to clean underneathand/or behind fins, gills, and the like. The lateral orientation of thenozzles may be +/−90° along the front to back of the fish.

Shoe 96 may be made of or include a slippery top surface (e.g., Delrinor Teflon or similar type material) so as not to harm the fish. The shoemay also function to scrape parasites off the fish body. As shown inFIGS. 8A-8C the arms pivot so at all times the spray head is kept veryclose to the fish body no matter its size and, for a given fish, closeto its small head, larger body, and smaller tail as the fish passesthrough the system. The spray head nozzle, in all cases, is also keptaligned to spray fluid at a selected optimized angle between 0 and 90degrees rearward along the fish body to more effectively dislodgeparasites and eggs from the fish while not harming scales, gills, andfins.

In this way, the jet spray is more effective: the cleaning spray is inair, the spray nozzle is kept a near constant distance from the fish nomatter its size or what portion of orientation anywhere along thecircumference of the conduit the fish is being treated, and the jetspray remains at a near constant angle relative to the fish body. Withthe cleaning sprays in air, little energy is lost from the spray as itmoves through air to the lice and fish surface. Alternatively, if thefish and spray jets are in water, as long as the spray nozzle is kept anear constant distance from the fish and a near constant angle relativeto the fish body, the spray pressure may be adjusted to remaineffective.

In FIGS. 10A-10C, the spray heads 80 are attached to four bar linkages100. Preferably, the spray heads are attached to top bar 102 thereof.Top bar 102 is then attached via pivots 104 and 106 to bars 108 and 110which are pivotably attached via pivots 112 and 114 to the conduit 42wall (the fourth “bar”).

By using a four bar or other linkage, the spray head nozzle is kept at aconstant distance from the fish body and at a constant angle relative tothe longitudinal axis of the conduit. The linkage keeps the spray headat a constant angle with respect to the pipe wall as the linkage and thespray head follows the outer surface of the fish moving by. Withpivoting shoes on the outer bar, the head will follow the fish surfaceand keep the jet spray angle constant with respect to the fish surfacewhile bar 102 stays parallel to the pipe wall. Compression spring 116between arms 108 and 110 may be used to bias the four bar linkage awayfrom the conduit (e.g., at a 90° angle relative to the longitudinal axisof the conduit wall).

In some examples, opposing spray heads may be 1-2 inches apart from eachother (when the arm is 90° to the conduit), the spray heads may bedisposed a near constant distance of 1-2 inches from the fish body, mayprovide a fluid spray at a pressure, for example, of 25-200 PSI and at aflow rate, for example, of 0.5-1 GPM to effectively remove parasites.Fan shaped sprays or other shapes may be used to optimize treatmentcoverage on the surface of the fish regardless of the shape and size ofthe fish. Different sets of nozzles may be in stages of the process togive maximum efficiency. The fan nozzles may overlap as needed for thebiggest fish (bigger circle) and thus the longest circumference anddistance between the nozzles. In one example, the final cleaning of thefish to remove salmon lice and eggs may be done by “curtain” nozzles.Flat shaped jets or jets that are made out of a slit in thecircumference of the tube that face inwardly may be used, to make thepressure variation less dependent on the distance from the head of thejet.

There are other means for adjusting the arms depending on the size ofthe fish and the conduit and for closely spacing the spray head nozzleswith respect to the fish. For example, FIG. 11 shows singulated andoriented fish in a vertical or angled conduit which here is in the formof a flexible conforming transversely or circumferentially or radiallyexpandable chute 42′ (e.g., a net, mesh, or the like). See, for example,U.S. Pat. No. 4,705,141, incorporated by reference herein.

The material of the chute may assist in scraping sea lice or otherorganisms off the surface of the fish in the second treatment zone 18.The material of the chute, however, should be configured to allow tirewater jet to reach the surface of the fish body. In this example, thereis a ring 120 disposed about the chute and the spray heads 80 (in thisexample 8 spray heads) are mounted on piston arms 122 extending inwardlyfrom the ring 120. Ring 120 may form a distributer for tire fluiddelivered to it via hose 92 and thus is configured to deliver the fluidto die individual spray heads via their respective arms. This radiallyexpandable chute may also act as a speed controller, so the fish isconstantly treated equally over its length passing the nozzles at acontrolled speed.

The piston arms may extend and retract based on the size of fish 27 inthe chute and the area being treated (e.g., head, body, tail) to keepthe spray nozzles of the spray head at a constant or near constant closedistance to the surface of fish 27. Preferably, the spray nozzles of thespray heads are oriented to spray rearwardly along the body of fish 27to effectively remove parasites and to prevent damage to the scales offish 27. The piston arms may be actuated.

One or more sensors 130 may be used to sense the distance of the body offish 27 from the ring 120 (or, alternatively, a nozzle). The output ofthe sensor(s) may be fed to a processor (not shown) which then drivesthe actuators of the piston arms accordingly to keep the spray heads ata desired distance to the fish body. The sensor subsystem could be basedon capacitance, for example, wish the exterior of chute 42′ includingmarkers which can be sensed by the sensor(s). Other sensor subsystemsmay be used. In other examples, the nozzles are attached to the materialof the chute or sleeve. See FIGS. 12-14.

The ring/piston arrangement shown in FIG. 11 may be used, in addition,in conjunction with conduits 42 a, 42 b, and 42 c. FIG. 2, as wellprovided there are orifices in the conduits for the spray heads andpiston arms. In some examples, the second treatment zone includes onlyone conduit. In other examples, the second treatment zone includesmultiple conduits. The nozzles may be used in multiple stages, multipleangles, and/or orientations. Also sensors may be employed to targetsingle salmon lice or more dense populations to make the process morecost effective. This process could also contribute to counting and/or toverily the quality of the cleaning process in a cost effective way. Alsopossible is a closed-loop control system with real-time monitoring ofkey parameters to ensure consistent quality e.g. salinity, temperature,O2, CO2, number of fish processed, and the like, the amount of sea liceremoved per period of lime and the like. Data could be gathered andanalyzed over time to provide optimal treatments amongst the individualtreatment centers or groups of treatment centers.

The result in any embodiment is a more effective treatment method andsystem which is cost-effective and which is ecologically sound.

FIG. 15 shows how the nozzles are configured to maintain a constant jetangle to the surface of the fish and how the nozzles maintain a constantwater jet force along the surface of the fish (e.g., adjusting thenozzles so they are kept at a constant or near constant distance fromthe fish).

FIG. 16 shows an embodiment where two drive belt assemblies urge fishfrom a treatment tank to another location. The belts may be mesh like inconstruction so nozzles spray a fluid from inside one or both beltassemblies.

Although specific features of the invention are shown in some drawingsand not in others, this is for convenience only as each feature may becombined with any or all of the other features in accordance with theinvention. The words “including”, “comprising”, “having”, and “with” asused herein are to be interpreted broadly and comprehensively and arenot limited to any physical interconnection. Moreover, any embodimentsdisclosed in the subject application are not to be taken as the onlypossible embodiments. Other embodiments will occur to those skilled inthe art and are within the following claims.

In addition, any amendment presented during the prosecution of thepatent application for this patent is not a disclaimer of any claimelement presented in the application as filed: those skilled in the artcannot reasonably be expected to draft a claim that would literallyencompass all possible equivalents, many equivalents will beunforeseeable at the time of the amendment and are beyond a fairinterpretation of what is to be surrendered (if anything), the rationaleunderlying the amendment may bear no more than a tangential relation tomany equivalents, and/or there are many other reasons the applicant cannot be expected to describe certain insubstantial substitutes for anyclaim element amended.

What is claimed is:
 1. A continuous system for removing parasites fromfish, the system comprising: a downwardly angled fluid spray treatmentconduit: a motorized fish conveyor apparatus including a conduit withwater and a treatment compound therein transporting fish from a pen tothe downwardly angled fluid spray treatment conduit; and adjustablespray nozzles in the downwardly angled treatment conduit closely spacingthe spray nozzles with respect to the fish and each connected to a fluidsource for dislodging parasites from the fish.
 2. The system of claim 1in which the motorized fish conveyor apparatus includes an Archimedesscrew.
 3. The system of claim 1 in which the motorized fish conveyorapparatus includes a coiled conduit attached to a motorized shaft. 4.The system of claim 1 further including a plurality of spaced sets ofarms associated with the downwardly angled fluid spray treatmentconduit, each set of arms including circumferentially spaced arms, eachsaid arm carrying at least one said spray nozzle.
 5. The system of claim4 further including means for adjusting said arms relative to theconduit.
 6. The system of claim 5 in which said arms include a distalshoe for engaging the fish and each nozzle is fixed to the shoe.
 7. Thesystem of claim 6 in which said distal shoe is pivotably attached to thedistal end of said arm.
 8. The system of claim 5 in which said arms arepivotably attached to the conduit and biased away from the conduit. 9.The system of claim 5 in which each said arm constitutes a bar linkagepivotably attached to the conduit.
 10. The system of claim 9 furtherincluding a spring associated with the bar linkage biasing it away fromthe conduit.
 11. The system of claim 5 in which the spray nozzles arerearwardly angled.
 12. A continuous method for removing parasites fromfish, the method comprising: transporting fish from a pen to adownwardly angled fluid treatment conduit via a motorized fish conveyorapparatus including a conduit with water and a treatment compoundtherein; automatically adjusting spray nozzles in the downwardly angledfluid spray treatment conduit to closely space the spray nozzles withrespect to the fish to dislodge parasites from the fish.
 13. The methodof claim 12 in which the motorized fish conveyor apparatus includes anArchimedes screw.
 14. The method of claim 12 in which the motorized fishconveyor apparatus includes a coiled conduit attached to a motorizedshaft.
 15. The method of claim 12 father including a plurality of spacedsets of arms associated with the downwardly angled fluid spray treatmentconduit, each set of arms including circumferentially spaced arms, eachsaid arm carrying at least one said spray nozzle.
 16. The method ofclaim 15 further including adjusting said arms relative to the conduit.17. The method of claim 16 in which said arms include a distal shoe forengaging the fish and each nozzle is fixed to the shoe.
 18. The methodof claim 17 in which said distal shoe is pivotably attached to thedistal end of said arm.
 19. The method of claim 16 in which said armsare pivotably attached to the conduit and biased away from the conduit.20. The method of claim 16 in which each said arm constitutes a barlinkage pivotably attached to the conduit.
 21. The method of claim 20further including providing a spring associated with a bar linkagebiasing it away from the conduit.
 22. The method of claim 16 in whichthe spray nozzles are rearwardly angled.